LU-13453 osd-ldiskfs: do not leak inode if OI insertion fails

LU-13453 osd-ldiskfs: do not leak inode if OI insertion fails

osd_create() should destroy just created inode if OI insertion
fails.

also fixes lustre_index_restore() to drop nlink for object to
be removed.

the patch adds two tests:
 - ENOSPC on OI insertion
 - ENOSPC on .. insertion, i.e. directory block allocation

Signed-off-by: Alex Zhuravlev <bzzz@whamcloud.com>
Change-Id: I2a5db657c7dab54b8dc2c50bc29365d5ee754a2e
Reviewed-on: https://review.whamcloud.com/38235
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Mike Pershin <mpershin@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>